1. Field of Invention
The present invention relates to an antenna. More particularly, the present invention relates to a planar reconfigurable antenna.
2. Description of Related Art
Antenna is not only a critical element in many wireless communication systems, but it also affects the overall performance of the systems. Generally speaking, tending to be subject to the affects of multiple-paths and signals on the same frequency, omni-antennas and panel-antennas may cause problems in wireless transmission and limit the system capacities.
To resolve the above-mentioned problems, technologies regarding reconfigurable antennas and smart antennas are proposed. In a wireless communication system, the system can change the parameters of a reconfigurable/smart antenna to achieve better communication quality. Examples of the parameters include direction, gain, and polarization. As a result, reconfigurable/smart antennas are wildly applied in communication systems such as digital television systems, wireless local networks, hand-hold electronic apparatuses (such as cell-phones, notebook computers, Netbooks, Smartbooks, UMPCs), and global positioning system.
However, a reconfigurable/smart antenna often has many antenna elements and a complex and enormous feeding and distribution network. Accordingly, the reconfigurable/smart antenna also has a high cost and a large size. In addition, because a reconfigurable/smart antenna can change its parameters according to the environment, its physical embodiment is generally quite complicated.